Yarn-changing device for circular knitting machines

ABSTRACT

A DEVICE FOR SITUATING A SELECTED ONE OF A PLURALITY OF DIFFERENT YARNS AT A KNITTING STATION IN A CIRCULAR KNITTING MACHINE. THE DEVICE INCLUDES A PLURALITY OF YARN-CHANGING MEANS SUPPORTED BY A SUPPORT MEANS FOR MOVEMENT BETWEEN REST AND CHANGING POSITIONS WITH EACH YARN-CHANGING MEANS SITUATING THE YARN CONTROLLED THEREBY AT A KNITTING STATION WHEN THE YARN-CHANGING MEANS IS IN ITS CHANGING POSITION. A DRIVE MEANS IS COMMON TO ALL OF THE YARNCHANGING MEANS FOR DISPLACING THEM FROM THE REST TO THE CHANGING POSITION, WHILE A SELECTING MEANS IS SITUATED BETWEEN THE DRIVE MEANS AND THE YARN-CHANGING MEANS FOR TRANSMITTING MOVEMENT OF THE DRIVE MEANS ONLY TO A SELECTED ON THE YARN-CHANGING MEANS. A PLURALITY OF YARN-CLAMPING-AND-CUTTING MEANS RESPECTIVELY COACT WITH THE PLURALITY OF YARN-CHANGING MEANS.

Och 1971 ERNST'DIETER PLATH 3,513,404

YARN-CHANGING DEVICE FOR CIRCULAR KNITTING MACHINES Filed Aug. 9, 1968 3 Sheets-Sheet 1 6 Elm. I wasi'ii/ l A INVENTOR. ERNST-'DIETER PLATH ATTORNEY Oct. 19, 1971 ERNST'DIETER PLATH 3,613,404

YARN-CHANGING DEVICE FOR CIRCULAR KNITTING MACHINES 3 Sheets-Sheet 2 Filed Aug.

INVENTOR. ERNST-DIETER PLATH ATTORNEY Och 1971 ERNST-DIETER PLATH 3,613,404

YARN-CHANGING DEVICE FOR CIRCULAR KNITTING MACHINES Filed Aug. 9, 1968 I5 Sheets-Sheet l5 INVENTORI ERNST-D1 ETER PLATH ATTORNEY United States Patent 3,613,404 YARN-CHANGING DEVICE FOR CIRCULAR KNITTING MACHINES Ernst-Dieter Plath, Tailfingen, Germany, assignor to Mayer & Cie Maschinenfabrik, Tailfingen, Germany Filed Aug. 9, 1968, Ser. No. 751,470 Claims priority, application Germany, Aug. 31, 1967, M 75,374 Int. Cl. D04b 15/60 US. Cl. 66-440 8 Claims ABSTRACT OF THE DISCLOSURE A device for situating a selected one of a plurality of different yarns at a knitting station in a circular knitting machine. The device includes a plurality of yarn-changing means supported by a support means for movement between rest and changing positions with each yarn-changing means situating the yarn controlled thereby at a knitting station when the yarn-changing means is in its changing position. A drive means is common to all of the yarnchanging means for displacing them from the rest to the changing position, while a selecting means is situated between the drive means and the yarn-changing means for transmitting movement of the drive means only to a selected one of the yarn-changing means. A plurality of yarn-clamping-and-cutting means respectively coact with the plurality of yarn-changing means.

BACKGROUND OF THE INVENTION The present invention relates to yarn-changing devices for circular knitting machines.

In particular, the present invention relates to that type of yarn changing device where there are a plurality of yarn-changing means selectively actuated for situating a selected one of a plurality of different yarns at a knitting station, this selection being made, from a suitable pattern control unit, through a selecting member controlled by the latter unit.

There are a wide variety of known devices for changing yarns of knitting machines, these devices being known as striping units of the knitting machines. Through these yarn-changing devices it is possible to interchangeably knit with different yarns at a knitting station. The conventional yarn-changing devices are arranged so as to be stationary with respect to the cam components of the knitting machine. In this case the yarn-changing devices are primarily designed for circular knitting machines having rotary needle cylinders and stationary circular actuating cams. For each yarn of the yarn-changing device the latter is provided with its own clamping device and its own cutting device, with both of the latter devices being combined into a common unit.

Conventional structures of the above type are relatively complex to control and actuate, and the structures thereof require an undesirably large amount of space.

SUMMARY OF THE INVENTION It is accordingly a primary object of the present invention to provide a yarn-changing device which will avoid the above drawbacks.

In particular, it is an object of the invention to provide a yarn-changing device which is exceedingly compact so that it will only occupy a small amount of space as compared to conventional devices of this type.

Also, it is an object of the invention to provide a yarnchanging device composed of a relatively small number of simply constructed elements enabling the device to be controlled and actuated in a manner which is far simpler and far more efficient than has heretofore been posice sible, while at the same time reducing the cost of the structure as compared to conventional structures of the above type.

With the structure of the invention there are a plurality of yarn-changing means supported for movement between rest positions and changing positions where the plurality of yarn-changing means will respectively feed different yarns to the knitting structure of the machine. A common drive means is provided for all of the yarnchanging means for displacing them between their rest and changing positions, while a selecting means is situated between the common drive means and the plurality of yarn-changing means for transmitting movement of the drive means only to a selected one of the plurality of yarn-changing means, so that only a selected yarn will be displaced to the knitting station.

The plurality of yarn-changing means take the form of yam-changing fingers respectively movable in predetermined planes between their rest and operating positions while the drive means which is common to all of these fingers is in the form of an elongated member extending across all of the fingers and spaced therefrom. The selecting means takes the form a swing-lever situated between the drive means and the fingers and capable of being angularly displaced by the pattern structure of the machine to a location in alignment with a selected yarnchanging finger so that when the drive means is actuated only the selected finger will displace its yarn to the knitting station. A plurality of yarn-clamping-and-cutting means are respectively provided for the plurality of yarnchanging means and coact therewith to be directly actuated thereby. The rotary structure of the knitting machine carries a cam means which has a stepped cam construction coacting with the drive means for actuating the latter, and because of this stepped cam construction the selected yarn-changing finger will be displaced by the drive means from its rest position to a first intermediate or operating position and then to a second operating or changing position.

In order to achieve the direct actuation of the yarnclamping-and-cutting means, each yarn-changing finger has at least a pair of cams. These cams directly engage the yarn-clamping-and-cutting means for directly actuating the latter.

In accordance with the invention each yarn-clampingand-cutting means includes a pair of yarn-clamping members, one of which is stationary and the other of which is swingable and a pair of yarn-cutting members, one of which is stationary and the other of which is swingable. All of these stationary and swingable components of the plurality of yarn-clamping-and-cutting means are arranged one next to the other coaxially with respect to each other. The yarn-changing finger of each yarn-changing means acts with its cams on the swingable yarnclamping member which by way of a coupling means is coupled to the swingable yarn-cutting member, so that both of these members operate together in response to the direct action of the yarn-changing finger on the swingable yarn-clamping member with which it coacts.

According to a further feature of the invention all of the movable and swingable components of all of the yarn-clamping-and-cutting means are situated beside each other in a row on a pair of shafts, and a single spring means which is common to all of the latter components acts to press them against each other on the shafts.

BRIEF DESCRIPTION OF DRAWINGS The invention is illustrated by way of an example in the accompanying drawings which form part of this application and in which:

FIG. 1 is a fragmentary, schematic partly sectional ele- 3 vation taken in a radial plane of the circular knitting machine at the region where the yarn-changing device of the invention is located, the yarn-changing means being shown in FIG. 1 in side elevation in a rest position;

FIG. 2 illustrates the parts of FIG. 1 in a position where a selected yarn-changing means has been displaced to its yarn-changing position;

FIG. 3 is a fragmentary partly schematic top plan view of the yarn-changing device of the invention;

FIG. 4 is a fragmentary exploded perspective illustration showing the cam-carrying end of a yarn-changing finger in its operating position together with parts of the yarn-clamping'and-cutting means actuated thereby;

FIG. 5 shows the parts of FIG. 4 in the position they take when the illustrated yarn-changing finger is in its rest position;

FIG. 6 is an exploded perspective illustration of the swingable member of the pair of yarn-clamping members; and

FIG. 7 is a perspective view of the yarn-changing device illustrating the thread path therethrough.

DETAILED DESCRIPTION The structure of the invention is illustrated in the drawings in a more or less schematic manner with the various views showing not only the details of the structure but also the different positions taken by the structure.

The particular yarn-changing device shown in the drawings is designed to hold six different yarns and thus is provided with six yarn-changing means each of which takes the form of a yarn-changing finger 1 stamped from suitable sheet metal. The series of yarn-changing fingers 1 are supported for swinging movement between rest and Operative positions, and for this purpose they are situated beside each other on a common shaft 2 about which they are capable of swinging between the positions indicated in FIGS. 1 and 2. The yarn-changing device of the invention permits only a single yarn to be knitted at any one time.

For this purpose a selecting means is provided for selecting the yarn-changing finger which is displaced to its yarn-changing position so as to situate the yarn controlled thereby at the knitting station. This selecting means includes a selecting lever 4 in the form of a swing-lever capable of swinging about a pivot shaft 3 which is horizontal so that the selecting lever 4 swings up and down and coacts with a selected finger 1 to actuate the latter. The pivot shaft 3 is carried by a block 6 which is in turn fixed to a shaft 5 supported for rotary movement about its vertical axis, so that in this way the selecting means 4 I will be horizontally swung, in the direction indicated by the double-headed arrow shown in FIG. 3, to a location where the tip of the lever 4 distant from the shaft 3 will be aligned with a selected yarn-changing means 1. The alignment of the selecting lever 4 with a selected yarnchanging means 1 is effected by means of an adjusting lever 7 fixed to the shaft 5 so as to determine the angular position of the shaft 5 and thus of the lever 4. This lever 7 itself is acted upon by an unillustrated Bowden cable which is actuated from the pattern unit of the circular knitting machine, which in a well-known manner is set up to provide a predetermined knitted pattern.

A drive means is common to all of the yarn-changing means 1 but is situated at the side of the selecting lever 4 opposite from the plurality of yarn-changing means 1, so that the movement of the drive means, although it is common to all of the yarn-changing means, will be transmitted through the selecting means only to the selected yarn-changing means. This drive means includes an elongated driving member in the form of a bar 8 extending across all of the yarn-changing means 1 with the selecting lever 4 situated between the bar 8 and the members 1. The bar 8 is fixed to a vertical plunger 9 and is urged upwardly by a return spring 10. Through the plunger 9 the bar 8 is displaced downwardly in opposition to the return spring 10 from the upper rest position shown in FIG. 1 to the lower operating position indicated in FIG. 2. The vertical displacement of the plunger 9 which brings about vertical displacement of the bar 8 is produced from a rotary cam means 11 which is carried by and rotates with the rotary components of the circular knitting machine and which has a camming surface engaging the top end of the plunger 9. Thus, the top end of the plunger 9 acts as a cam follower maintained in engagement with the rotary cam structure 11 by the spring 10.

Each yarn-changing means includes a yarn-guiding eye 12 carried by the finger 1 and through which a yarn is guided after first passing through a stationary guide eye 13 of the device. From the guide 12 of each yarn-changing means the yarn extends into the region of a yarn-clampingand-cutting means situated at the region 14 in FIGS. 1-3. The details of each yarn-clamping-and-cutting means are illustrated in FIGS. 46 and described below.

When the selecting means 4 has, for example, the position illustrated in FIG. 3, then the end yarn-changing finger 1 shown at the lower part of FIG. 3 and visible in side elevation in FIGS. 1 and 2 has been selected. FIGS. 1 and 2 show in side elevation the lower yarn-changing finger 1 of FIG. 3, and the remaining yarn-changing fingers are situated behind the yarn-changing finger 1 which is visible to the greatest extent in FIGS. 1 and 2.

As long as the rotary cam means 11 does not displace the plunger 9 downwardly, the drive means 8 remains in its upper rest position, and the end finger 1 which is visible in FIG. 1 remains in its upper rest position, a spring means yieldably maintaining the end of finger 1 shown in FIG. 1 at its upper position, which is its position of rest. However, as soon as the cam means 11 displaces the plunger 9 downwardly, so that the drive means 8 is displaced along its driving stroke from the rest position of FIG. 1 to the operating position of FIG. 2, the selecting lever 4 is swung downwardly around the pivot shaft 3 and presses the yarn-changing finger 1 about the shaft 2 of the support means into the lower working position of the yarn changing finger 1 position shown in FIG. 2. It is to be noted, however, that the cam means 11 has a stepped construction providing for displacement of the selected finger 1 in a pair of steps or stages situating the finger I initially at an intermediate operating position and then at the lower changing position of FIG. 2. When the selected finger 1 has been displaced to the yarn changing position shown in FIG. 2, the yarn guided thereby is in the region of a yarn-catching hook 15 which is actuated in a known manner to draw the selected yarn, which is now at the knitting station, into the machine to be knitted therein.

In the exploded illustration of FIG. 4, the yarn-changing finger 1 is shown at its lower changing position corresponding to the operating position illustrated in FIG. 2. In this position an upper cam 101 which is carried by the finger 1 presses downwardly upon a swingable member 16 of a pair of yarn-clamping members which include in addition to the swingable member 16 a stationary member 17. The swingable member 16 of the pair of yarn-clamping members 16, 17 is supported for swinging movement on a shaft 18 which extends parallel to a second shaft 19. While only the shaft 18 extends through the member 16 to support the latter for swinging movement, both of the shafts 18 and 19 pass through openings respectively formed in the stationary clamping member 17, so that in this way this member 17 is maintained stationary.

Furthermore, the same pair of shafts 18 and 19 extend through a pair of yarn cutting members, one of which is stationary and the other one of which is swingable, and which also are provided, together with the pair of yarn clamping members, for each yarn-changing finger 1. The pair of yarn-cutting members of each yarn-clamping-andcutting means includes a swingable cutting member 20 and a stationary cutting member 21. In this case also the swingable member 20 is supported for swinging movement only by the shaft 18 which extends through an opening of the member 20, while both of the shafts 18 and 19 extend through a pair of openings formed in the stationary cutting member 271.

A coupling means is provided for coupling the swingable members of the pair of yarn-cutting and pair of yarn-clamping members to each other for swinging movement as a unit, so that when the swingable yarn-clamping member 16 is moved the yarn-cutting member 20 will move therewith. This coupling means includes a motiontransmitting pin 24 fixed to and projecting from the member 16 in the direction parallel to the shaft 18, and this motion-transmitting pin 24 is received in an opening 25 formed in the swingable cutting member 20, the lower edge of the stationary yarn-clamping member 17 having a configuration which will permit movement of the pin 24 without interference during swinging of the members 16 and 20 together.

As is apparent from FIG. 3, all of the members of all of the yarn-clamping-and-cutting means of the yarnchanging device of the invention are arranged in a row in series on the pair of shafts 18 and 19 where they are pressed one against the other by a single spring means 22 which is common to all of these members and which engages the end one of the members shown at the lowermost part of FIG; 3 to press the latter toward the opposite end one of the members, with all of the intermediate members being pressed against each other between these end members. This entire arrangement of all of the yarnclamping-and-cutting means is indicated at 14 in FIGS. 1-3.

As may be seen from FIG. 4, when the yarn-changing finger 1 is in its lower changing position, its cam 101 displaces the swingable members '16 and 20 to release positions releasing the yarn-clamping members 16 and 17 from a position clamping a yarn and the yarn-cutting members 20 and 21 from a position cutting the yarn, and thus the yarn 23 is released so as to be freely guided to the knitting station of the machine which is not illustrated in 4. The cam 11 is constructed so as to have a pair of camming steps bringing about displacement of the selected finger I initially from its rest position into an intermediate position where the yarn guided thereby is engaged by the catching hook 15 and is fed to the knitting station where it is knitted into the fabric. When the first step of the cam 11 thus displaces the selected finger 1 to its intermediate position, the movable clamping mem ber 16 has not yet been displaced to its release position so that the selected yarn remains clamped during the formation of the first loops with the newly fed yarn. The second step of the cam 11 completes the movement of the finger 1 through its second stage to its lower operating position shown in FIGS. 2 and 4, so that in this way the selected finger 1 is swung further in a clockwise direction downwardly, thus bringing about by way of its cam 101 the displacement of the member 16 in a counter-clockwise direction to release the end of the selected yarn.

FIG. illustrates the return movement of a yarnchanging finger 1 towards its rest position. In this latter position the yarn-changing finger which previously was in its lower operating position is automatically displaced back to its rest position upon selection of another yarnchanging finger by the selecting lever 4, since the newly selected finger actuates a release means 28 in the form of a. lever extending across and common to a plurality of pawls 26 (see FIG. 3) respectively provided for the plurality of fingers 1 for releasably maintaining a selected finger in its lower yarn-changing position. A return spring 27 is operatively connected with each finger 1 for returning it to its rest position when the pawl 26 is displaced to its release position, and thus it is by way of the spring 27 that the previously selected finger 1 is automatically returned upwardly to its rest position.

As is apparent from FIGS. 1-3, each yarn-changing finger 1 has a lower rear release cam 29' which actuates the release lever 28 when the selected finger '1 is displaced downwardly to its operating position. Thus, the yarnchanging fingers are constructed in such a way that only upon the swinging of a selected finger from its intermediate to its second or lower operating position will the lever 28 be actuated to release the pawls 26, so that only at this time will be previously selected finger return to its rest position, and now the swingable clamping mem ber for the newly selected yarn is actuated by the cam 101 to release the newly selected yarn.

When the previously selected finger returns to its rest position, the lower cam 102 thereof engages the coacting swingable member 16 of the pair of clamping members and turns it in a clockwise direction on the shaft 18. During the return movement the yarn 23 guided by the previously selected finger is guided into the region of the yarn-clamping-and-cutting means coacting with this previously selected finger, so that the parts for the previously selected finger will assume the position shown in FIG. 5. Thus, lower cam 102 of the finger 1 moves the swingable member 16 of the pair of clamping members in a clockwise direction upwardly so that the yarn 213 is clamped between the movable clamping member 16 and the stationary clamping member 17. By Way of the coupling means 24, the movable member 20 of the pair of cutting members is also swung upwardly in a clockwise direction so as to cut the yarn 23 between the movable cutting member 20 and stationary cutting member 21, thus separating the previously selected yarn from the knitting structure.

As is apparent from FIG. 2, the configuration of the cam 11 is such that at the region of the end of the movement of the selected finger 1 to its lower feeding position it is fed initially slightly beyond the lower feeding position bringing about the movement of the lever 28 by the cam 29 upwardly to a position displacing all of the pawls 26 to the release positions, and then bringing about the release of the clamping member 16, while just at the very end of the movement the cam 11 provides for a slight return of the selected lever 1 sufficient to displace the lever 28 downwardly from the pawls 26 thus permitting the pawl 26 which coacts with the selected finger 1 to engage behind a tooth at the upper rear thereof, and of course, the cam 101 will now 'be situated slightly higher than the clamping member 16 which remains in its lower release position due to the frictional pressing of the series of clamping and cutting members against each other as described above. It is only when the cam 102 engages the released clamping member 16 upon the return of the previously selected finger l1 to its rest position that this latter member 16 is returned to its clamping position while the member 20 is swung to cut the yarn.

In order to achieve a reliable clamping action between the swingable clamping member 16 and the stationary clamping member 17, in a manner which is to a large extent independent of manufacturing tolerances, the swingable clamping member 16, as shown in FIG. 6, is composed of a base member formed with a recess 161, directed toward the stationary member 17. In this recess 161 there is an elastically yieldable insert 162 made of spongy rubber. Then a small clamping plate 163 of spring steel is mounted on the base member 4160, this member 163 being fixedly riveted to the base plate 160, together with the motion-transmitting pin 24 of the coupling means, but otherwise resting resiliently against the base member 160 as result of the elastic insert 162. Between this resiliently supported clarnping plate 163 of the movable clamping member 16 and the side surface of the stationary clamping member 17, which is directed toward the swingable clamping member 16, the yarn 23- is clamped and reliably held.

The yarn-changing device of the invention is, as compared to prior-art yarn-changing devices, composed of a relatively small number of individual parts assembled into a compact unit, and the structure of the invention operates in an extremely reliable manner. Although the invention is illustrated and described with reference to one preferred embodiment thereof, it is to be understood that it is in no way limited to this said embodiment but is capable of numerous modifications within the scope of the appended claims.

What is claimed is:

1. In a yarn-changing device for circular knitting machines having rotary needle cylinders and stationary actu ating cams, a plurality of yarn-changing means for respectively feeding different yarns to a knitting station, support means supporting each of said plurality of yarnchanging means for movement between a rest position and a working position, a single drive means common to all of said yarn-changing means for displacing each of them from said rest to said working position, selecting means situated between said single drive means and said plurality of yarn-changing means for transmitting movement from said drive means only to a single selected yarnchanging means, so that through said selecting means the drive from said drive means will act only upon a selected yarn-changing means to displace the latter from its rest to its Working position, and a plurality of yarn-clampingand-cutting means, each one of said plurality of yarnclamping-and-cutting means being respectively operatively connected to one of said plurality of yarn-changing means to be fully directly actuated thereby during movement of a selected yarn-changing means both to and from the working position to release the yarn upon actuation of a selected yarn-changing means to the working position and to sever and clamp the yarn upon return of the selected yarn-changing means to the rest position.

2. The combination of claim 1 and wherein said plurality of yarn-changing means are in the form of elongated fingers supported by said support means for movement in predetermined planes between said positions, said drive means including an elongated drive member extending across all of said fingers and displaceable toward and away from the latter, and said selecting means including a swing-lever swingable to positions respectively aligned with said fingers and situated between said elongated drive member and fingers, so that by aligning said swing-lever of said selecting means with a selected finger, said drive means will transmit its motion through said selecting means to the selected finger.

3. The combination of claim 1 and wherein a rotary cam means coacts with said drive means for actuating the latter, said cam means having a stepped cam construction coacting with said drive means for actuating the latter to displace a selected yarn-changing means first from its rest position to an intermediate position, and then from said intermediate position to a lowermost position.

4. The combination of claim 1 and wherein each yarnchanging means has at least a pair of cams for actuating the yarn-clamping-and-cutting means which coacts with said yarn-changing means.

5. The combination of claim 1 and wherein each yarnclamping-and-cutting means includes a pair of yarn-clamping members, one of which is stationary and the other of which is swingable, and a pair of yarn-cutting members, one of which is stationary and the other of which is swingable, and all of said members of all of said yarn-clampingand-cutting means being coaxially arranged with respect to each other.

6. The combination of claim 5 and wherein each yarnchanging means has cams coacting with a swingable yarn-clamping member for actuating the latter member, and each yarn-clamping-and-cutting means including a coupling means coupling said swingable yarn-clamping member to said swingable yarn-cutting member, so that the swingable members operate together in response to action on the swingable yarn-clamping member by the cams of each yarn changing means.

7. The combination of claim 6 and wherein all of said members of all of said yarn-clamping-and-cutting means are arranged in a row one next to the other, a pair of shafts supporting all of the latter members in said row with one of said shafts supporting said swingable members for swinging movement and the other of said shafts supporting said stationary members and spring means common to all of said members of all of said yarnclamping-and-cutting means for pressing them against each other in said row on said shafts.

8, The combination of claim 1 and wherein a plurality of releasable pawl means respectively coact with said plurality of yarn changing means for releasably retaining them in their working positions, and release means common to all of said pawl means and actuated by displacement of a selected yarn-changing means to its working position for releasing the plurality of pawl means so that whichever yarn-changing means was previously in its working position is released for return to its rest position.

References Cited UNITED STATES PATENTS 2,122,845 7/1938 Raulston et a1 66-140 2,893,228 7/1959 Shortland 66140 2,940,285 6/1960 Saunders 66140 2,961,858 11/1960 Wiesinger 66140 ROBERT R. MACKEY, Primary Examiner 

